
There are legal requirements for the display of prices applying to all hospitality and tourism premises (see link).
Accommodation
If you offer accommodation as part of a business, you must ensure the price information that is given for accommodation and other services is not misleading. A price list should be prominently displayed with full information indicating the range of prices inclusive of compulsory service charges and VAT (where applicable). If you charge more than your advertised price, you could be guilty of giving a misleading price indication.
Bars/Licensed Premises/Restaurants
Before they make a purchase, consumers must have information relating to the main characteristics of the product (e.g. brand of drink), the price, quantity, and trading name and details of ownership of the premises.
There are specific requirements concerning the quantities that some alcoholic drinks must be served in, particularly with regard to beer (one third of a pint, a half pint, or multiples of a half pint), gin, rum, vodka and whisky (25ml, 35ml, or multiples of these), and wine (by the bottle or specified quantities by the glass or carafe)
(Source: Trading Standards Institute)
Trading Standards Institutetradingstandards.gov.uk